Will Flex revolutionize weed control?

Bill O'Neal says he got rid of his last cultivator five or six years ago. Now he may be about to dispense with his post-directed spray rigs.

O'Neal, who manages 5,500 acres of cotton at Allendale Planting Co., in Shelby, Miss., isn't one to shed equipment lightly. But he thinks new technology may make it possible to control weeds much more efficiently than with a post-directed sprayer.

The new technology is Roundup Ready Flex, genetically modified cotton that allows growers to spray glyphosate herbicide over-the-top after the four-leaf stage of development. Some say the Flex gene may revolutionize cotton weed control.

“We sprayed Roundup at planting and again at the four-leaf stage,” says O'Neal, one of about 160 growers who planted Roundup Ready Flex varieties in farm-scale experimental plots across the Cotton Belt this year. “Then we made two more overhead applications in the Flex cotton.”

O'Neal post-directed two other applications of Roundup in a field of Deltapine 555 BG/RR planted along side the Roundup Ready Flex Beltwide Cotton Genetics variety on Highway 61 north of Shelby.

“I can tell you that going over-the-top of the cotton with a 12-row broadcast sprayer was much faster than going through it with a 12-row post-directed sprayer,” said O'Neal. “And putting the herbicide out in a high clearance sprayer with a 90-foot spray boom was even better.”

For growers like O'Neal — who have a considerable amount of acreage to cover — the Flex technology may not have come at a better time. (Monsanto expects to introduce the Roundup Ready Flex technology in 2006 if foreign regulatory clearances are received this winter.)

Adopting Roundup Ready Flex would be one more step in the transformation of O'Neal's cotton production philosophy.

“If you had told me 20 years ago that there would be a time when I wouldn't plow cotton, I would have strongly disagreed,” he said. “Now I don't own a cultivator. I'm convinced the savings from no-till and minimum-till farming are keeping many of us in business — especially with these fuel prices.”

David Skelton, who operates Capstone Farms in Winterville, Miss., thinks Roundup Ready Flex cotton could make a difference in his bottom line. Skelton planted 40 acres of Roundup Ready Flex in 2005.

“The last tractor in that field was the one with the planter,” he said. “I hope it works out because it has the potential to save us some money. But it has to yield before I'll plant it.”

Skelton said he applied Roundup as needed on the 40 acres of Stoneville 5242 RR Flex. “We didn't layby because the Roundup Ready Flex block looked as clean as the rest of the cotton after layby,” he noted. “We never went back to that field with anything but a John Deere 4720 sprayer with a 90-foot boom.”

That could mean tremendous labor savings, he said. “With these high-clearance sprayers you can cover 600 to 700 acres a day with one person. You can't do that with a row cultivator or a post-directed sprayer.”

Although he would not predict yields, Skelton was marveling at the way the 2005 harvest was turning out. He picked three bales of cotton plus on some of the 2,400 acres of cotton he grew last year.

“Everyone had a good crop in 2004,” he said. “We got almost no rain on this (non-irrigated) field this year. We shouldn't be harvesting a crop given the amount of moisture we had.”

On Allendale Planting Co., which is located farther from the Mississippi River than Winterville, O'Neal irrigated his Roundup Ready Flex experimental field four times. He said he was “guardedly optimistic” about yields.

“We've had a good year, but a very expensive year,” he said, referring to the fuel costs for the four irrigations. “We started out very dry and had to furrow water some of the cotton to get it out of the ground. But it looks good now.”

O'Neal said farmers have relied on hooded sprayers to help apply glyphosate to sensitive crops, but that the latter may also see less use in the future.

“We've had coverage issues with the hoods,” he said. “Sometimes with the hooded sprayer, you can't get good coverage of the weeds. And if it rains, you may find yourself waiting to get back in the field with the hooded sprayer. With the new technology, if you get in a bind, you can still spray.”

Some growers are finding they may make fewer applications of glyphosate on Roundup Ready Flex than the earlier Roundup-tolerant varieties. Jeff Hux, a grower in Sikeston, Mo., said his Flex varieties required only three over-the-top applications of glyphosate compared to four in his conventional Roundup Ready cotton.

“We were able to save a herbicide application in the Roundup Ready Flex cotton because we were able to wait until more weeds emerged before treating,” he said. “I felt I got more for my dollar by delaying the application.”

Monsanto began working to develop the Flex gene shortly after it introduced Roundup Ready cotton in 1997 because of the limited application window for glyphosate over the top in the latter.

Farmers are limited to two applications of glyphosate 10 days apart and prior to the fifth-leaf stage of plant development with the current Roundup Ready technology. Applications can be made from emergence up to seven days before harvest on Flex cotton after it is commercially introduced.

“I think you can see why we think the world is about to change,” said Rick Rice, director of marketing for Beltwide Cotton Genetics, a new cotton seed breeding company that decided to forego placing the conventional Roundup Ready in its varieties so they could offer them with the new advanced Flex technology.

“We think Roundup Ready Flex has the potential to revolutionize cotton production because of the labor savings and ease of use,” said Rice, speaking at a BCG Media Day in Seminole, Texas that featured a BCG Flex variety in a large-plot demonstration.

“They say that Roundup Ready cotton made the plow extinct,” said Skelton. “Roundup Ready Flex may make the hooded sprayer and post-directed spray rigs extinct.”